Well, we could use the JVM and Java bytecode. Then, third-party developers could compile their code written in Java, Scala, or other JVM-compatible languages to Java bytecode and post that bytecode to the blockchain. Another possibility is CLR with Mono (could support the C# language). The good thing about both choices is that we don't need to use process isolation to protect against invalid memory access (which if allowed could let the third-party code corrupt the ChainBase database) assuming that any submitted bytecode that uses unsafe operations and unauthorized native APIs are disallowed by the system. By doing it this way with these managed languages (i.e. not allowing languages like C or C++), we can avoid doing costly IPC (inter-process communication). Nevertheless, how to handle a generalized object mapping solution between the safe VM and the raw data available in the ChainBase memory region is still not very clear to me.

Keep in mind that there may be some licensing issues with the JVM. I think the licensing issues are actually better with Mono now that Microsoft acquired Xamarin (they relicensed Mono under MIT).